Current time: 01-17-2018, 11:20 AM

Hello There, Guest! Register
facebook
Instagram
Eddles

Bass gene pool

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
#1
It has often been mentioned on these forums about how important it is to conserve the bigger bass for the benefit of the gene pool. We need to consider that the gene pool in SA is mostly from a few surviving fingerlings way back in 1928.
There may have been some dilution with the Florida’s brought into SA in the 80’s but still our population is genetically small or what?

I’m not a geneticist but maybe someone on this site can offer some insight into this theory?
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
BWG
#2
riprap you are spot-on! the gene pool is tiny for SA's bass. There has probably been some selective pressure due to environmental conditions but the original fish are essentially all related. As you mention,there is information as to at least one subsequent introduction of bass into SA but I don't have that information on hand. This would have brought a lot of variation into the gene pool. Fish are much more tolerant of inbreeding than mammals and so this is not such a huge problem

As for a big old female, she has had many seasons to pass her genes on, should they have been superior in any way and so this is not a significant loss to the gene pool!

we have to remember that in most cases, each dam was also only stocked with a few fish to start with! this reduced the gene variation in each event
Reply
#3
The following is from a hatchery in the States:

A very common problem that we hear is “Why have my bass stopped growing to a larger size?” There are usually only 2 reasons this happens: 1) inadequate food in your pond or lake, or 2) the pond or lake has not been stocked in many years. What happens is the gene pool burns itself out, the bass inbreed and eventually become stunted. The answer to this problem is to simply restock your pond or lake. However, if this inbreeding was left unchecked for many years, then the answer may have to be to get rid of the bass and restock with new bass. This is why it is so important to monitor and manage a pond or lake. This problem can also happen to a fish hatchery, especially if selective breeding is not used. This effect is not limited to just largemouth bass and is seen in fish such as yellow perch.
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
#4
And some more....

CASTAIC - Attempting to strengthen the bass gene pool, volunteers motored into shallow coves on Castaic Lake on Wednesday and released 1,500 bass fingerlings that they hope will mature and breed with existing fish.

Friends of Castaic Lake, a nonprofit group that raised and donated more than $3,000 to purchase the fish, sought coves rich with underwater vegetation that they hope will provide a protective habitat for the Florida largemouth bass fingerlings.

``We're trying to enhance the gene pool here,'' said Terry Kratzer, a volunteer. ``That's different from stocking the lake. This particular strain of fish has a strong gene pool, so down the line we hope to have stronger and bigger bass like in the past.''

The 1,500 fingerlings, about 3 months old and no bigger than 3 inches long, were brought from Willow Creek Fisheries in Central California.
.
About four boats were loaded with buckets of fish and sent to a dozen coves, where volunteers released the tiny fish in hopes they have a better chance at surviving to reproductive age.

``We've got three types of bass in Castaic right now. But the striped bass feed on the other fish and we want these fingerlings to have a chance to strengthen the population,'' said David Thomas, a Castaic resident and Friends volunteer.

The fish release, the first of its kind in the body of water encased in 34 miles of shoreline, will be a success if 30 percent of the fingerlings survive and reproduce, Thomas said.

``We're out here for the enhancement of the fish, so people can enjoy the lake for a long time,'' he said.

Friends of Castaic Lake, founded in 1983 to support and enhance the recreation area, holds four night-bass tournaments every summer, with 40 percent of the entrance fees helping to fund causes like the fish release
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
#5
of course a hatchery would have that to say! they want to sell their fish Smile

lots of small bass in the dam and very few large ones is a management issue and not a genetic issue. When you remove the fish that are large enough to eat fingerling bass there is nothing to control their numbers and what you find is that they eat all the available fodder and none of them can make it to a large size again. They get older and older but never bigger as there is enough food to survive but not to grow. This is why the states have slot limits, in order to keep big fish to spawn and to allow small fish to grow up.

I have seen this first-hand in pristine dams that have never been fished before. Initially, you find a lot of large bass and a small number of juveniles. As soon as word gets out and the hook and cook brigade removes all the big fish then the dam very quickly becomes over-populated with those 200-400g fish and no big fish are caught again for years. This is not genetic in-breeding, this is just what happens when too many big fish are removed.

the only way to remedy this situation is to remove a lot of the fish in that size range, leaving small fish and the few large fish that are left behind!
Reply
#6
My pond is 30 to 40 years old so i have no idea what bass i had in it. I figured it had just the native northern bass in it thats found here in texas. I put in tigre bass last year and gonna put in some of overtons floridas this year. You might as well do it, it cant hurt anything. I mean its a fact that florida bass grow larger and live longer then any other bass.
Reply
BWG
#7
Maratur - welcome boet.
We might have to check with "Bergie" on this one as he was around at that time?? Rumour has it that he verified the first batch here in 1928!

Seriously though, there is an article in the bass biology thread on tiger bass, see <!-- l --><a class="postlink-local" href="http://www.bassfishing.co.za/bassingnews/modules.php?name=Forums&file=viewtopic&t=5792">modules.php?name=Forums&file=viewtopic&t=5792</a><!-- l -->

A florida F1 x is more suited to the cooler regions in SA whilst florida do well in the more tropical areas and along the coast. Florida's have almost permanent pms and fishing for them is very frustrating at times thus yes for genetics and better fishing a combination might work well? If we could, the ideal would be to import some fresh genetics of northerns.
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
#8
Fish Genetics: Hope or Hype?

<!-- m --><a class="postlink" href="http://www.bassresource.com/fish_biology/fish_genetics.html">http://www.bassresource.com/fish_biolog ... etics.html</a><!-- m -->
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
#9
HYBRID BLACK BASS:

Biologists recognize that hybridization between freshwater fish is more common than for any other type of vertebrate. Sunfish, including bluegills, redear, green sunfish, and pumpkinseed, readily hybridize, particularly in altered habitats, where spawning areas are limited, or when one species is introduced into waters where another species had solely existed. Some crosses have been recommended for stocking private waters.

Due to habitat alterations and widespread introduction of black bass species outside their native ranges, hybrid black bass are increasingly common. While anglers may find occasional catches of hybrids a curiosity, the loss of genetic adaptations honed over millions of years, which occurs with such genetic mixing, is not obvious; yet it represents a threat to the quality of bass fishing.

Meanmouth Bass: In the mid-1960s, Dr. William Childers and colleagues at the Illinois Natural History Survey began studies of centrarchid (sunfish family) hybrids. In the lab, they produced some oddballs—crosses of largemouth bass with warmouth, green sunfish, and bluegill. Crosses with crappie and rock bass failed.

The researchers noted that different black bass species didn’t hybridize when stocked in ponds with members of another species (i.e., all males of one species with all females of another). But fertilizing largemouth eggs with smallmouth sperm produced viable offspring that reproduced among themselves and with both parental species.

The term “meanmouth bass” was born when Childers observed a school of largemouth-smallmouths attacking a female swimmer. “The bass leaped from the water and struck her on the head and chest,” he wrote, “and drove her from the pond.” On another occasion, he watched meanmouths attack a dog that ventured into shallow water.

Though indications of hybrid vigor were evident in aggressiveness and fast growth, high mortality and low reproductive rates for the hybrids led to a halt of this investigation in the 1980s. Childers cautioned that backcrossing of hybrids with parental species would be harmful, since gene flow between the species would reduce the fitness of populations as maladaptive genes were introduced. Over 30 years ago, he urged caution in mixing bass subspecies and even geographically separated populations of fish of the same species.

In nearly all cases of hybridization outside the lab, smallmouth have been involved. Geneticist Dr. Dave Philipp, colleague of the late Dr. Childers, noted that fertilization of largemouth bass eggs with smallmouth sperm resulted in more successful crosses than the reciprocal cross (largemouth male and female smallie). The aggressive male smallmouth bass may be an instigator when introduced into waters outside its natural range where spawning sites are limited, or in altered habitats such as reservoirs.

When smallies were added to newly constructed Squaw Creek Reservoir in Texas, they soon hybridized and backcrossed with both northern and Florida subspecies of largemouths that were already in the impoundment. In 1993, Rich Fry caught an 8-pound 3-ounce bass from a Pennsylvania mine pit that was genetically identified as a first-generation hybrid of a largemouth and a smallmouth bass.

More Crosses: By the late 1960s, stocking of spotted bass in central Missouri had led to hybridization and genetic swamping of smallmouth populations. Today, backcrossed mixes of spots and smallies are increasingly common in central Missouri streams and in reservoirs such as Table Rock, where several state records have been set, up to 5 pounds 10 ounces. Due to their fighting power, they’re locally known as “meanmouth bass,” but this confuses the original meaning of the term. In 2006, an 8-pound 5.6-ounce spot-smallmouth hybrid was caught in Oklahoma’s Veteran’s Lake, a new state record and the largest black bass hybrid on record.

In north Georgia and Alabama, introductions of smallmouths into spotted bass water and of spots into smallie water led to hybridization and mixing of genotypes, compromising the adaptive characteristics of each species in these waters.

Beginning in 1974, smallmouths were stocked into central Texas streams where only native Guadalupe bass had existed. Within a decade, extensive hybridization and backcrossing occurred. To preserve the few remaining pure populations of Guadalupes from extermination by genetic swamping, smallmouth stocking has ceased here, sanctuaries have been established, and captive-bred Guadalupes planted in streams to buoy their numbers.

Hybridization of smallmouth and redeye bass also has occurred in the Upper Cumberland River watershed of Tennessee, where introduced redeyes hybridized with smallmouths, resulting in more than half the bass being crosses. A research group including Dr. Philipp has recently labeled the Florida bass a separate species—not a subspecies of largemouth as traditionally thought—based on analysis of mitochondrial DNA. Many studies of this cross have been done over the last 30 years.

While some short-term hybrid vigor may be noted, long-term loss of fitness is inevitable when black bass hybridize. Recent investigations show that “outbreeding depression,” a measureable descriptor of loss of fitness, occurs when populations are mixed.

While it may be hard today to find black bass populations unaffected by stock transfers, it’s imperative to keep them pure by restricting any transfers into those watersheds, and to limit further mixing of stocks of black bass.

<!-- m --><a class="postlink" href="http://www.in-fisherman.com/2012/08/24/hybrid-black-bass/" onclick="window.open(this.href);return false;">http://www.in-fisherman.com/2012/08/24/ ... lack-bass/</a><!-- m -->
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
#10
Where can we get some of those meanmouth bass?

:blue-badgrin: :blue-badgrin: :blue-badgrin:
Reply
#11
If it is correct that fish can genetically adapt to their surroundings, then one logical way of bumping up the gene pool would be to mix fish from far and different locations which have adapted over many generations, or not.......?
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
BWG
#12
Binfield Kassie.I have to catch a humdinger this weekend.
Hopefully the light is switched on and not off for the weekend
Reply
#13
You've caught enough humdingers in your time.
It's my turn now!

As for the lights - we're not depending on Eksdom this weekend, so the lights should be on - as long as the fuel tank stays wet inside!
Reply
#14
That's the thing with genetics and especially in the E. Cape - just check how my thread gets hijacked for a club outing.........wahahaaaaa!! Leave some for the rest of us hey!
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
Reply
#15
riprap Wrote:That's the thing with genetics and especially in the E. Cape - just check how my thread gets hijacked for a club outing.........wahahaaaaa!! Leave some for the rest of us hey!


We will check on the gene pool at Binfield this weekend :eusa_dance:
We may even catch a feesh - if we don't, we'll hit Away With The Fairies in Hogsback :eusa_whistle:
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)